This sub-Forum is for posts on the basics of Bonsai, handy tips and other useful ideas to get you started on your own Bonsai. If you are new to Bonsai, read here before posting queries as you may find the answer. Ask questions on the main Bonsai forum and if the answer is of general interest it will end up here.

Thought I might do something slightly different for a change. If you notice in some of my photos there are trees set on Rocks.

I’ll do three separate topics, one showing Sandstone, one showing Limestone and one showing Lava rocks otherwise I’ll have close to forty photos on this one topic.

After I’ve done these three posts, I might do a new topic on how to actually put a tree over a rock, and I’ll select one of the rocks in these topics, if you’d like to see it done.

Rock selection for ‘Root over Rock’ style needs a bit of thinking about. A round smooth rock or large pebble is no good for a few of reasons. I don’t know about anyone else, but I’ve never seen a tree growing on a smooth rock. Also, a smooth rock or pebble would do nothing to enhance the tree or convince the viewer that it looked natural. There would be nowhere for a seed to germinate – it needs some moisture and some medium to grow in. Usually, trees – commonly figs grow in crevices or recesses in rocks or rock faces where there is a bit of leaf litter or something to sustain it till the roots can grow down to the ground. In other cases, a tree can grow from the base of the rock and in the case of figs send out aerial roots that can grip the rock and grow all over it. I have seen Maples growing on what looks like huge outcrops of flat rocks but what’s happened there is that a seed has got lodged in a crack and managed to send a root far enough down through the crack to sustain it till the tree has started to grow. Roots have then grown from the base of the trunk and spread over the flat rock till they’ve found some soil.

So, if you’re interested in putting a tree over a rock, you need one with some character – or one you can carve character into. Sandstone, Limestone and Lava rock are three that come to mind that can be quite easily carved. Granite, Basalt and the like can be worked but I’m not a stone mason, so I’d leave those to the experts. About the only reason you’d need to carve into any rock would be to put grooves down over it to suit the positions of the roots on the tree.You can buy specialist ‘fabricated’ rocks from Bonsai nurseries that are composed of real pieces of rock stuck together. Some of these can look quite good with a tree on them because they’re usually very rugged looking.

Finding a rock with good character in it doesn’t necessarily mean it will be the right one for the tree you want to put on it. The tree might not be shaped in the way that would suit the rock or the roots might be in totally the wrong places. Anyway, I’ll explain that further when I do the post on how to put a tree over a rock.Below are some of the rocks I have here that I’ve collected over the years from various places around the country. None have been bought; they’re all from the wild. I’ve placed them in different positions and even upside down to show there can be different ways of looking at them and different ways they can be used. The pot they are standing in is 500mm wide (to give you some idea of the size of the rocks). When you look at the photos, try and picture a tree positioned in different places on them.

As I post the photos I’ll say where I got them from.

Sandstone.

All these came from just off the side of the road about 5km north of Katherine in the Northern Territory. I was on a convoy with four other RAAF Drivers delivering new 4WD’s to Darwin and we had stopped for a ‘leak’. I went back a few months later to collect some more, but unfortunately the Main Roads had bulldozed the whole of that particular side of the road to widen it and everything had disappeared.

Rock 1.

Rock 2.

Rock 3.

Rock 4.

Rock 5.

Rock 6.

Rock 7.

This one came from the side of the road leading to Shark Bay in Western Australia.